It blamed “terrorists” for the attack that it said left an unspecified number of people dead and wounded between Jaramana and the adjacent rebel-held town of Mleha.

The Syrian Observatory for Human Rights said 16 soldiers were killed in the blast and clashes that followed.

Lebanon said nine of its citizens kidnapped in March last year by rebels in Syria have been freed, with signs that two Turkish pilots whose abduction in Beirut was linked to their capture may be freed.

Lebanese Prime Minister Najib Mikati said that Qatar, which along with Turkey supports Syria’s opposition, played a role in securing the release of the nine Shiites.

Ankara said the detention of the two Turkish Airlines pilots kidnapped near Beirut airport in August was now close to ending.

“Very favorable developments are under way concerning the two Turkish pilots. This matter has been largely settled,” Turkish Minister of Foreign Affairs Ahmet Davutoglu said, adding that the pair could be freed “within hours or days.”

The Syria conflict erupted in March 2011, when Syrian President Bashar al-Assad’s regime launched a bloody crackdown on democracy protests inspired by the Arab Spring uprisings.

It is now estimated to have killed more than 115,000 people, forced millions to flee the devastated country as refugees and trapped hundreds of thousands.

In a strongly worded statement, the US condemned the regime’s relentless siege of Eastern Ghouta and Moadamiyet al-Sham, two rebel-held neighborhoods on the capital’s outskirts.

There were “unprecedented reports of children dying of malnutrition-related causes in areas that are only a few miles from Bashar al-Assad’s palace in Damascus,” US Department of State spokeswoman Jen Psaki said.

“The regime’s deliberate prevention of the delivery of lifesaving humanitarian supplies to thousands of civilians is unconscionable,” she added.

The call came as UN-Arab League envoy Lakhdar Brahimi was to arrive in Cairo at the start of a regional tour aimed at paving the way for peace talks.

The international community hopes to convene a peace conference in Geneva next month, but prospects for the talks remain unclear, with Syria’s opposition divided and due to vote next week on whether to take part.

In Geneva, spokeswoman Khawla Mattar said Brahimi would meet in Cairo with Egypt’s foreign minister as well as the head of the Arab League.

The full itinerary for the trip has not been finalized, she added, but stops in Syria and Damascus ally Iran are expected.

US Secretary of State John Kerry, who has also been pushing for the conference, is to head to Europe next week for talks on Syria.